GCN Circular 25346
Subject
LIGO/Virgo S190814bv: ATLAS forced photometry non-detections of DESGW candidates
Event
Date
2019-08-15T18:07:51Z (6 years ago)
From
O. McBrien at QUB <omcbrien02@qub.ac.uk>
O. R. McBrien, S. Srivastav, K. W. Smith, D. R. Young, M. Dobson, S. J. Smartt, J. Gillanders, P. Clark, D. O'Neil, S. Sim (QUB), L. Denneau, H. Flewelling, A. Heinze, J. Tonry, H. Weiland (IfA, Univ. Hawaii), A. Rest (STScI), B. Stalder (LSST), C. Stubbs (Harvard)
We report ATLAS (Tonry et al. 2018) forced photometry at the position of the candidate objects reported by the DESGW team (GCN 25336) following the NS-BH event S190814bv (The LIGO Scientific Collaboration and the Virgo Collaboration, GCN 25324).
AT2019nmd (desgw-190814a) and AT2019nme (desgw-190814b) were reported in GCN 25336. Both objects were discovered on MJD 58710.278 at coordinates RA=12.870848 deg Dec=-22.471377 deg for AT2019nmd and RA=12.635660 deg Dec=-22.226027 deg for AT2019nme.
We have performed forced photometry at the locations of these transients covering the period of time from their discovery epoch to 100 days prior (MJD 58610). The fields of AT2019nmd and AT2019nme were visited on 16 separate nights during this time by ATLAS. A typical observing night sees each field observed 4 ��� 5 times with 30 second exposures. For both AT2019nmd and AT2019nme we find no significant (SNR > 3 sigma) flux in this time to a limiting magnitude of >19.9 mag and >20.1 mag respectively, mostly in the ATLAS-orange filter, for a typical 30 second exposure.
The most recent ATLAS non-detections at the locations of these candidates occur on MJD 58709.630 at >19.5 mag in the ATLAS-cyan filter for AT2019nmd and on MJD 58709.630 at >19.4 mag in the ATLAS-cyan filter (both at a SNR limit of 3 sigma).
This work has made use of data from the Asteroid Terrestrial-impact Last Alert System (ATLAS) project. ATLAS is primarily funded to search for near earth asteroids through NASA grants NN12AR55G, 80NSSC18K0284, and 80NSSC18K1575; byproducts of the NEO search include images and catalogs from the survey area. The ATLAS science products have been made possible through the contributions of the University of Hawaii Institute for Astronomy, the Queen's University Belfast, and the Space Telescope Science Institute.